In the process of using LED, the loss of photons generated by radiation recombination when emitted outwards mainly includes three aspects:
Chip internal structure defects and material absorption; photon reflection loss at the exit interface due to difference in refractive index;
And the total reflection loss due to the incident angle being greater than the critical angle of total reflection. Therefore, a lot of light cannot exit from the chip.
By coating a transparent adhesive layer with a relatively high refractive index on the surface of the chip, since the adhesive layer is between the chip and the air, the loss of photons at the interface is effectively reduced, and the light extraction efficiency is improved.
In addition, the role of potting glue also includes mechanical protection of the chip, stress relief, and as a light guide structure.
Therefore, the packaging material is an indispensable part of the LED lighting device. The packaging material largely determines the light efficiency and service life of the LED device, which directly affects the energy-saving efficiency and life of the LED lighting material.